Ultrasonic testing is used for a variety of different applications from thickness measurements to flaw detection in aerospace and structural materials. The transducers used for these tests must be selected carefully to obtain the required spatial resolution and penetration. Damping, frequency, and focal properties required for a specific test often require the use of separate transducers. Transducers have heretofore been changed manually in order to obtain the characteristics desired for different tests. This is a time-consuming operation, particularly for multichannel testing and rapid inspection of large test pieces.
Since ultrasound is strongly reflected at air/solid or air/liquid interfaces, test pieces are often immersed in water or streams of water supplied by jets or bubblers to provide the coupling medium.
Various scanning techniques to provide pulsed laser radiation beams on a unitary path are exemplified in the prior art, for example U.S. Pat. No. 3,924,937.
Use of rotatable reflecting mirrors for light beams are known in the prior art as shown for example in U.S. Pat. No. 3,475,552.
Reflector means for reflecting ultrasonic energy from a plurality of transducers is known in the prior art from U.S. Pat. No. 3,107,521.